From: Rick (ccie_2003@hotmail.com)
Date: Tue Oct 15 2002 - 16:31:43 GMT-3
I'm trying to understand Why, and how to properly use this command. Could
someone further explain this command and give an example how to use it, or how
it may be used on a lab scenario?
Thanks,
Rick
To allow the tuning of the IGRP or Enhanced IGRP (EIGRP) metric calculations,
use the metric weights router configuration command. To reset the values to
their defaults, use the no form of this command.
metric weights tos k1 k2 k3 k4 k5
no metric weights
Syntax Description tos
Type of service. Currently, it must always be zero.
k1-k5
Constants that convert an IGRP or EIGRP metric vector into a scalar
quantity.
Defaults
tos: 0
k1: 1
k2: 0
k3: 1
k4: 0
k5: 0
Usage Guidelines
Use this command to alter the default behavior of IGRP routing and metric
computation and allow the tuning of the IGRP metric calculation for a
particular type of service (ToS).
If k5 equals 0, the composite IGRP or EIGRP metric is computed according to
the following formula:
metric = [k1 * bandwidth + (k2 * bandwidth)/(256 - load) + k3 * delay]
If k5 does not equal zero, an additional operation is performed:
metric = metric * [k5/(reliability + k4)]
Bandwidth is inverse minimum bandwidth of the path in bps scaled by a factor
of 2.56 * 1012. The range is from a 1200-bps line to 10 terabits per second.
Delay is in units of 10 microseconds. The range of delay is from 10
microseconds to 168 seconds. A delay of all ones indicates that the network is
unreachable.
The delay parameter is stored in a 32-bit field, in increments of 39.1
nanoseconds. The range of delay is from 1 (39.1 nanoseconds) to hexadecimal
FFFFFFFF (decimal 4,294,967,040 nanoseconds). A delay of all ones (that is, a
delay of hexadecimal FFFFFFFF) indicates that the network is unreachable.
Table 19 lists the default values used for several common media.
Table 19: Bandwidth Values by Media Type Media Type Delay Bandwidth
Satellite
5120 (2 seconds)
5120 (500 megabits)
Ethernet
25600 (1 ms)
256000 (10 megabits)
1.544 Mbps
512000 (20,000 ms)
1,657,856 bits
64 kbps
512000 (20,000 ms)
40,000,000 bits
56 kbps
512000 (20,000 ms)
45,714,176 bits
10 kbps
512000 (20,000 ms)
256,000,000 bits
1 kbps
512000 (20,000 ms)
2,560,000,000 bits
Reliability is given as a fraction of 255. That is, 255 is 100 percent
reliability or a perfectly stable link.
Load is given as a fraction of 255. A load of 255 indicates a completely
saturated link.
Examples
The following example sets the metric weights to slightly different values
than the defaults:
router igrp 109
network 192.168.0.0
metric weights 0 2 0 2 0 0
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